Railway track circuit apparatus



Oct. 26, 1931. B. E. O'HAGAN 1,327,825

RAILWAY TRACK CIRCUIT APPARATUS Filed June 18, 1930 [mm/ g 3 A 1 l INVENTOR,

.0'H an, BY

tax-W Patented Oct. 20, 1931 J UNITED STATES SWITCH & SIGNAL COMPANY, or swissvarn rnlvnsxnvnnm, A" CO PORATION OF PENNSYLVANIA.

Application filed June 18,

My invention relates to railway track circuit apparatus, and particularly to apparatus of the type involving a main track circuit, one of the rails of which is divided to form an auxiliary track circuit. One object of my invention is the provision of means, in apparatus'of this character, for preventing bobbing of the track relay for the auxiliary track circuit when a car alternately bridges and shunts the auxiliary track circuit.

I will describe one form of apparatus embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing. one form of apparatus embodying my invention.

Referring to the drawing, the reference character A designates a railway track, the rails 1 and 1 of which are divided by'insulated joints 2 to form a main track section C-D. This section is provided with the usual track circuit comprising a source of current E connected across the rails at one end of the section, and a main track relay R connected across the rails at the other end of the section. The source of current E, as here shown, is a transformer, the secondary of which is connected with the track rails and the primary of which is connected with a source of alternating current which is not illustrated in the drawing.

The track rail 1 is-further divided by insulated joints 2 to form a short insulated section 3, and the main track circuit current is conducted around this section by a wire 6. The section 3 is provided with an auxiliary track circuit comprising a transformer E" and an auxiliary track relay B". One terminal of the secondary of transformer E is connected with the rail 1 and the other terminalis connected with insulated section 3 of rail 1 Similarly, one terminal of track relay R is connected with rail 1 and the other terminal is connected with insulated section3 of rail 1 'I It will be seen from the foregoing that each track relay is normally energized, that track relay R will become deenergized when a train enters section OD, but that track relay R will not become deenergized until a por- RAILWAY TRACK cInouIsuAirAnArus i BERNARD E, OHAGAN, or SWISSVALE, PEnivsYLvAnimnssreivon ro THE union 1930 lseii ai ubileresa i tion of the train enters insulated-mil sec- 1-,i 'n3;- ;:.I "if I; I I 5.5:. f With the apparatus thus far described, 1 if a car having-fa" wheelbase longer than 'th'e? length ofl-insulat'ed rail section 3shou'ldpass overthis section, relay "R? would become ell-- ergized whenthecar bridge's the section. In orden-toiavoid this contingency, I have "pro; videdf a shunt around one "of the insulated joints 12 which shu11t1 7 includes a back con relay R but when thecar bridges section 3, so that, no wheel lies within this section, relay R will remain deenergized because of a shunt'path which passes from the left hand terminal of relay R through back con-' tact 4t, resistance 5, the wheels and axles of nal of relay R".

When a car moving toward the'right enters the short section 3, it will immediately deenergize relay 3*, and after this car has passed a certain distance beyond section 3 i the voltage across the terminals of relay R will rise to such value that this relay will occur, can be, varied by adjusting the resistance 5.- I

' the car, and rail 1 to the right-hand termiagain pick up. The point at which this will Apparatus embodying my invention is I particularly well adapted for use in connece tlon with the control of highway crossing signals, and may, for example, be used in sy'sterns such asthose disclosed and claimed in application for Letters Patent of the United States filed by G. W. Baughman' on July 17, 1930, serial No. 468,538.

.Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within. the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a main section of rail Way track having one rail divided by insulated joints to form a short auxiliary section, a track circuit for said main section including a source of current connected across the rails at one end of the section and a main track relay connected across the rail at the other end of the section, a trak'ircu'it for said auxiliary section includinglasource ofcurren-t--and* an auxiliary track relay and a shunt around one of said insulated joints including the back contact track relay. 2. Incombination, a main section of rails Way track having one rail divided by insu latedjoints to form a short auxiliary section a track circuit for said main section'includinga source'of current connected across the rails atone end ofthe section and a main track relay connected acrossthe rail at the other end, of the section, a track circuit 'for said auxiliary section including. a source of current and an auxiliary track relay-, and a shunt around one of said insulated; joints including the back contact of said auxiliary track relay and an adjustable resistance. r In testimony whereof I aflix my signature.

BERNARD E. QI-IAGAN..

of the auxiliary 

